The grass may be greener in the country, and the carpets softer in the city, but--as the two amiable mouse couples in Brett's rich interpretation of the timeless fable finally resolve--``There's no place like home.'' Brett's ( The Mitten ; Trouble with Trolls ) version of how they arrive at their wise conclusion serves up a sumptuous visual feast. The art on each double-page spread (alternately devoted to urban and rural settings) is brimming with droll details; exquisite patterns appear on clothing, china and rugs; and imaginative borders range from silk cord to pottery shards to dandelions. The text also conveys the culture gap between the city and the country mice with a good deal of humor. When she feels a raindrop on her head, the city-mouse wife asks, ``Is the bathtub leaking?''; and her natty husband proudly dons a new jacket (``so colorful and eye-catching''), not realizing that it will indeed catch a creature's eye--that of a large owl whose greedy clutches he barely escapes. Bound to be a standout among the season's picture book offerings. Ages 4-8. (Sept.)